The present invention relates to the field of grounding against the danger of electrostatic discharges (ESD) on multi-layer installations (MLI) used as heat protection of space satellites and structures.
In the course hereof, for convenience, acronyms known to specialists in the field will be used. We will not provide the explicit meanings thereof insofar as they are now accepted in the specific terminology. The grounding system of multi-layer insulations used as thermal protection for satellites and space structures is usually developed in such a manner as to have one or more points of electrical connection with the underlying structure in order to avoid the accumulation of electrostatic charges; these are potential causes of electrostatic discharges (ESD) which may damage or alter the characteristics of the multi-layer insulation itself and may create electrical interference and partially or completely damage the electronic apparatus present on board the space structure.
The present techniques for protection against ESD employ more than one grounding point on each MLI, which points are however, different from the points of attachment of the MLI to the underlying structure.
At each grounding point all the layers which form the multi-layer insulation (the outside one which faces space, the inside one which faces the structure and the intermediate ones) are in contact generally through a metallic material which may be a strip of aluminum sheet or thin washers of metal or of electro-conductive rubber. Another metallic element which may be a strip of metal sheet or a metal cable or wire is therefore used to connect each grounding point of the MLI, either to another grounding point on the contiguous MLI or on the underlying structure or on the structure of the satellite itself.
Such systems of effecting the grounding are complicated and require a large number of points in order to obtain the necessary reliability on each MLI; they are furthermore very laborious to construct and therefore increase the cost of construction, usually adding undesired weight to the MLI and therefore to the satellite or space structure. These problems are solved by the method of grounding which forms the object of the present invention.